The relationship between measures of cortical activity and autonomic measures of emotional arousal has not been adequately studied in mood disorders, and yet, this may be of critical importance for understanding findings of regional hemispheric activation in these disorders. The proposal uses a unique set of picture stimuli to investigate autonomic and central nervous system asymmetries during emotional processing in depressed patients and healthy controls. Bilateral electrodermal activity (EDA), electroencephalographic (EEG), and event-related potential (ERP) measures are recorded simultaneously, i.e., from the left and right hand from homologous sites over the left and right hemisphere. Emotionally arousing and matched neutral stimuli are used to study effects on these peripheral and central indicators of electrophysiological activity in 50 depressed patients and 50 healthy controls. Pictures of patients with dermatological diseases, one half before cosmetic surgery (negative) and one half after successful treatment (neutral), serve as stimuli differing primarily in emotional content. These stimuli will be briefly exposed to the left or right visual field, in order to stimulate each hemisphere separately. An important aim is to examine the relationship between autonomic and central measures of emotional reactivity in depressed patients as well as in healthy subjects in one paradigm. The study explores specific cortical regions that will display EEG/ERP asymmetries related to EDA asymmetries. The recordings of 30 channels of EEG will allow the use of current-source density techniques for topographic analysis of regional cortical activity. Symptom features of depression are also an important aspect of the study, with particular emphasis given to the relation of EDA, EEG, and ERP measures to symptoms related to emotional responsivity, in particular anhedonia. On a theoretical level, the investigators hypothesize advantage for processing emotional stimuli and a general reduction in electrodermal activity. A long-range clinical goal is to contribute toward the development of objective measures for assessing cortical and autonomic reactivity to emotional stimuli in depression.